Catalytic Conversions in Water. Part 23: Steric Effects and Increased Substrate Scope in the Palladium‐Neocuproine Catalyzed Aerobic Oxidation of Alcohols in Aqueous Solvents#

The steric influence of substituents on the 2‐ and 9‐positions of phenanthroline in the (2,9‐R 2 ‐1,10‐phenanthroline)palladium(II)‐catalyzed aerobic oxidation of 2‐hexanol was investigated by means of high throughput experimentation. (Neocuproine)Pd(OAc) 2 (RCH 3 ) was found to be a highly active catalyst for alcohol oxidation in 1 : 1 water/DMSO mixtures. The catalyst is unique in that it tolerates water, polar co‐solvents and a wide variety of functional groups in the alcohol. Turn‐over frequencies of >1500 h −1 were achieved and a series of alcohols was oxidised with 0.1 to 0.5 mol % of catalyst.